Individual differences in alcohol response (AR) are robust predictors of later alcohol-related problems over periods as long as 25 years. [Yet, there has been little effort to apply this knowledge about high risk patterns of AR to prevention/intervention programs. This is in direct contrast to concerted efforts to target other well- known markers of risk (e.g. family history of alcoholism). In order to move toward the application of high-risk patterns of AR to empirically supported interventions, we must address important gaps in the literature.] First, the specific pattern of AR that confers greatest risk is till not well understood. Although there is clear evidence that a low level of response to negative alcohol effects (e.g. drowsy, dizzy) is associated with increased risk for later problems, much less is known about other aspects of AR. To date, only one study has examined the relation between high arousal positive effects (e.g. excited, talkative) and later drinking outcomes, and there are no studies on the effects of low arousal positive effects (e.g. relaxed, calm) on risk fo later problems. This is a critical issue as stronger negative reinforcement motives for drinking are robust predictors of drinking problems. Second, prior longitudinal studies have evaluated AR in settings that are not representative of typical drinking contexts (e.g. solitary drinking in a laboratory). Thus, we know little about relations between AR in more real world drinking contexts and later risk for negative outcomes. [This information is vital as high risk patterns of AR that do not generalize to more real-world settings may have limited practical utility. The proposed study will characterize specific patterns of AR that predict subsequent alcohol-related problems, thereby allowing the direct application of information about AR-related risks to prevention and intervention efforts. Participants (n = 360; 50% female) will be randomly assigned to one of three drinking contexts (solitary lab, group lab, or group simulated bar) with beverage condition nested within each context (n = 70 alcohol; n = 50 placebo). This three group design will allow us to examine the impact of both social (solitary vs. group) and physical (lab vs. simulated bar) context on AR.] We will use a multi-method approach (explicit, implicit, behavioral, and biological measures) to assess the full range of AR, including effects that have not been examined in prior longitudinal studies (e.g. low arousal positive and high arousal negative effects). Following the placebo controlled alcohol challenge; we will track subsequent drinking behavior and alcohol-related problems using bi-annual surveys over a two year period (4 total assessments). [This study design will allow us to examine the full range of alcohol effects as predictors of future drinking and problems, and determine if relations between AR and later drinking outcomes are dependent on context.] Findings of the proposed study will provide the basis for disseminating more detailed information about specific high-risk patterns of AR, particularly patterns of AR that individuals are readily able to discern in typical drinking contexs (e.g. group drinking or drinking in a bar setting).]